Challenge 2: Anonymous, Tamperproof Polling

Devise a protocol for conducting an anonymous poll using a deck (or multiple decks) or playing cards. You may assuming each pollee may manipulate the deck without anything about the manipulations being observed.

A solution must have the following functional properties:

• The pollster can determine how many of the pollee's answer to "yes" to a yes or no question by examining the deck at the end of the protocol.

A solution must have the following security properties:

1. No information is revealed about any individual's vote to either the pollster or other pollees, even if up to two other parties collude.
2. No individual can effect the outcome by more than one vote.

Note: this may be impossible. A satisfactory solution is either a protocol with the desired properties, or a clear proof why no such protocol exists.

University of Virginia Department of Computer Science CS 588: Cryptology - Principles and Applications

cs588–staff@cs.virginia.edu